Biopharma & drug delivery · Iron deficiency anemia
Keylika
A two person Y Combinator startup building a dissolvable patch that delivers iron through the cheek instead of the gut or a vein. The preclinical data comes from rats and hamsters. No clinical trial or FDA filing has started.
A patch you hold in your cheek
Keylika’s pitch starts with a molecule small enough to slip through tissue that normally keeps things out. The company calls it KYLK01: a mixed ligand iron complex under 500 daltons, water soluble, built in the ferric state so it can hand off directly to transferrin, the protein that carries iron through the blood.
The molecule is loaded into a patch the company brands KEYPaxtek. Entrepreneur reported in April 2025 that the patch sticks to the inner cheek for less than 30 minutes before it finishes releasing its iron. ONdrugDelivery, in a June 2024 technical article written by the company’s own founders, described a related version dissolving fully in under an hour on porcine buccal tissue in lab testing. Either way, the idea is to get iron into the bloodstream through the mouth’s lining, called the buccal mucosa, which the founders’ article says is four to 4,000 times more permeable than skin.
No pill. No needle. No infusion chair.
The gap between a pill and an IV
Iron deficiency anemia sits in an odd spot in medicine: common, disabling, and stuck with two treatments that patients often can’t tolerate or can’t easily get. Oral iron supplements are cheap but absorb poorly, and higher doses bring on nausea, constipation and diarrhea that drive people to quit taking them. Intravenous iron works better but requires a clinical setting, carries a small risk of anaphylactic shock, and according to Keylika’s own website can run a patient a wait for a specialist referral and an infusion appointment.
The scale of the problem depends on which Keylika document you read. Y Combinator’s company page and Keylika’s own 2022 launch post put US iron deficiency at more than 30 million people and 1.6 billion worldwide. The company’s website, archived in May 2024, cited 15 million women and children in the US and 1.3 billion worldwide. Entrepreneur, in April 2025, cited over 10 million Americans and 1.3 billion worldwide. The figures move around, but the company has been consistent on where it wants to start: women of childbearing age with menorrhagia, heavy menstrual bleeding, a population it sizes at about 6 million in the US.
Two engineers, one from bionic eyes
Buddhadev P. “Buddha” Chaudhuri holds a PhD in drug delivery microsystems from Imec and KU Leuven in Belgium and did postdoctoral work at UC San Francisco. Before Keylika, according to the company’s website, he worked at Biolinq, a continuous glucose monitoring startup, and at Koniku, a synthetic biology company. Entrepreneur reported that his interest in the problem is personal: he told the outlet he has lived experience of iron deficiency himself.
His co-founder, Frederik Ceyssens, PhD, also trained at KU Leuven and brings a background the company describes as more than 150 published research articles and over 2,000 citations. Ceyssens has a separate identity in the medical device world: a LinkedIn profile lists him as co-founder and CEO of ReVision Implant, a neurotechnology company working on restoring sight to blind patients through retinal implants. Y Combinator’s company page for Keylika includes founder text describing an electrical engineering PhD and work on “tiny moving machines” and “nuclear space rockets,” alongside the ReVision mention, a biography that lines up with Ceyssens rather than with Chaudhuri’s drug delivery training, though the page does not clearly label which founder it belongs to.
From skin to cheek
Keylika joined Y Combinator’s Summer 2022 batch. Every public description of the product from that year through at least mid 2024, including Keylika’s own website, Y Combinator’s company page and an April 2024 International Business Times article, called it a wearable transdermal skin patch and, on the company site, gave the drug a product name, NistuFe.
By June 2024, the story had changed. In their own ONdrugDelivery article, Chaudhuri and Ceyssens introduced “the world’s first resorbable buccal patch for iron delivery,” describing an in vivo pharmacokinetic study in iron deficient hamsters rather than the rat studies cited earlier, and dropping the NistuFe name in favor of the molecule code KYLK01. By April 2025, Entrepreneur was describing the same buccal approach under a new brand, KEYPaxtek, and reporting that Keylika had just been accepted into Bakar Labs, a startup accelerator at UC Berkeley. No public statement from the company explains the switch from skin to cheek. The underlying molecule, KYLK01, appears to be the constant across both versions of the story.
What is proven, and what is still claimed
| Evidence | What the record shows | Source type |
|---|---|---|
| Delivery route | Described as a wearable transdermal skin patch from 2022 through at least mid 2024 (Y Combinator, Keylika website, IBTimes), then as a resorbable buccal patch from June 2024 onward (ONdrugDelivery, Entrepreneur, Bakar Labs). No public explanation for the change was found. | Differs across company statements |
| Lead molecule | KYLK01, a mixed ligand iron complex under 500 daltons, described by the company as a new molecular entity tailored for non-oral delivery. | Company-stated |
| Preclinical data | Rat proof-of-concept for intradermal delivery cited on the company website and by IBTimes (2024); a separate hamster pharmacokinetic study for the buccal patch, four animals per group, described in the founders’ own ONdrugDelivery article (2024). No independent replication found. | Company-stated |
| Clinical trials | No study for Keylika or KYLK01 found in a ClinicalTrials.gov search conducted for this profile on Sep 25, 2026. | Not found |
| Peer-reviewed publication | No paper on Keylika or KYLK01 found in a PubMed search for this profile. | Not found |
| FDA record | No 510(k), PMA or other FDA filing found under Keylika’s name. | Not found |
| Headquarters | Y Combinator’s company page lists San Francisco. Independent trackers Crustdata and a Whiteford Research aggregation both list Walnut Creek, California, and records reviewed for this profile listed both. | Differs from YC listing |
| Team size | Three people as of September 2026, up from about one at founding in 2022, according to Crustdata’s tracked headcount data. | Independent tracker |
| Accelerator | Accepted into Bakar Labs, a UC Berkeley biotech incubator, reported in April 2025. | Independent |
Read plainly: Keylika has a molecule and two rounds of small animal data, first in rats and then in hamsters, that it has described in shifting terms over four years. What has not shown up anywhere public is a clinical trial, an FDA filing, a peer-reviewed paper, or a settled account of what the product actually is.
What to watch
- Whether Keylika files an FDA Investigational New Drug application, the step before human testing can begin.
- A published, peer-reviewed account of either the rat or hamster data.
- Whether the company settles on one delivery format, skin or cheek, in its public materials.
- A named pharma partner. Entrepreneur reported in 2025 that Keylika was exploring partnerships to develop the technology further; none had been announced as of this profile.
In their words
“My background in microfabrication, materials science and drug delivery systems, together with the personal lived experience of iron deficiency myself, gave me unique insights into how we might solve this widespread problem,”
Buddhadev Chaudhuri, PhD, CEO and co-founder, to Entrepreneur, April 2025 · Independent
“We’ve developed a new small molecule drug that permeates the buccal mucosa and eliminates the GI side effects associated with oral supplements.”
Buddhadev Chaudhuri, to Entrepreneur, April 2025 · Independent
“Our buccal patch has been demonstrated as a platform drug delivery technology, one that can be used to deliver a wide range of molecules less than 10 kDa molecular size that suffer from poor oral bioavailability, directly into blood circulation without the need for injections.”
Frederik Ceyssens, PhD, CTO and co-founder, to Entrepreneur, April 2025 · Independent
“A novel transbuccal solution could be a valuable addition to available options if a therapeutically relevant dose can be delivered without significant side effects,”
Rondeep Brar, MD, clinical professor of medicine, hematology, Stanford School of Medicine, quoted by Entrepreneur, April 2025 · Independent, uninvolved clinician
“Keylika’s unique approach of delivering a more absorbable form of iron with a buccal patch can be a game-changer as it has the potential to achieve significantly higher efficacy minus the typical GI side effects of orals.”
Christy Evans, MD, obstetrician and gynecologist, Almond ObGyn, quoted by Entrepreneur, April 2025 · Independent, uninvolved clinician
“Our novel molecule is small in size, and tailored for a skin-based delivery system that bypasses the entire gastrointestinal tract, minimizing the associated side-effects. This results in superior absorption and better clinical outcomes,”
Frederik Ceyssens, quoted by International Business Times, April 2024 · Company-stated
“Innovation is imperative to combat the IDA epidemic effectively.”
Buddhadev Chaudhuri and Frederik Ceyssens, ONdrugDelivery, June 2024 · Company-authored
Related companies
Sources
- IndependentKeylika: Redefining the Standard of Care for Iron Deficiency Anemia, company profile
- CompanyLaunch YC: Keylika: Redefining the Standard of Care for Iron Deficiency
- CompanyTackling Iron-Deficiency Anaemia: a Leap Forward with a Revolutionary Buccal Patch
- IndependentKeylika Develops World’s First Buccal Patch for Iron Deficiency Anemia (IDA)
- IndependentBiopharma Startup Keylika is Redefining Iron Deficiency Anemia with a Novel Iron Drug Skin Patch
- CompanyKeylika website, home and technology pages
- Independent trackerKeylika, Headcount, Funding & Open Jobs
- Independent trackerKeylika, Funding Rounds & List of Investors
- Independent trackerKeylika, Funding, Investors & Signals
- Public recordEDGAR company and full text search for “Keylika,” no Form D or other filings found
- Public recordStudy search for “Keylika” and “KYLK01,” no studies found
Profile researched and written by Healthcare Discovery. Last updated September 29, 2026.
